Just use cmake or scons. In 2016, you should not hand write a single makefile !
A simple cmake/sconcs build file will be as simple as the one shown (or even simpler !) and it will definitively will be easier to integrate external dependencies if you have to.
A simple cmake/sconcs build file will be as simple as the one shown (or even simpler !) and it will definitively will be easier to integrate external dependencies if you have to.